DNA-based vaccines have the potential to be highly effective in various diseases. They are also less expensive, easy to mass produce and potentially safer alternative to currently available vaccines. Despite the recent success in various animal models, the prophylactic and therapeutic success of genetic immunization in humans is far from realization and awaits development of patient-compliant, efficient, safe, and practical gene delivery systems. Needle-free immunization through the skin is an excellent alternative to current delivery protocols because, (a) the skin is a rich environment for antigen presenting cells that are naturally designed for immune-surveillance and modulation and (b) it is a safer and more patient-compliant alternative to needled injections. Recent developments in cutaneous immunization using high-pressure mediated biolistic or powder delivery, has proven efficacious in several disease models. However, these require highly specialized devices and skilled personnel, which precludes their use in mass vaccination especially in third world countries. Self-applicable, patch-based delivery technologies using DNA nanoparticles can be significantly less expensive, yet highly effective strategy for cutaneous vaccination. This proposal describes plans to gather preliminary data on the efficacy of plasmid DNA and CpG oligos delivered via polymer-nanoparticles and chemical enhancers, on skin penetration and subsequent generation of immune response against encoded antigens. The specific aims are: (a) synthesis of biodegradable nanoparticles of different size and surface charge with plasmid DNA and CpG oligos adsorbed on the surface and formulating them with various skin penetration agents, (b) studying the efficacy of particle transport and dendritic cell uptake following delivery with chemical enhancers and iontophoresis and (c) immune response against the encoded antigen following cutaneous application with a patch. These studies will enable us to identify the critical parameters for cutaneous particle delivery and further optimize and develop a simple, needle-free, skin-patch type system for DNA immunization in specific disease models.